package com.alcj.common.vcode;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.LinearGradientPaint;
import java.awt.Paint;
import java.awt.RenderingHints;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Arrays;
import java.util.Random;

import javax.imageio.ImageIO;
/**
 * @author : chenxh
 * @version :v1.0
 * @Package : com.alcj.common.vcode
 * @Description :(静态验证码)
 * @date : 2017/10/13 9:20
 */
public class JpgCaptcha {
        //使用到Algerian字体，系统里没有的话需要安装字体，字体只显示大写，去掉了1,0,i,o几个容易混淆的字符
        public static final String VERIFY_CODES = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ";
        private static Random random = new Random();


        /**
         * 使用系统默认字符源生成验证码
         * @param verifySize    验证码长度
         * @return
         */
        public static String generateVerifyCode(int verifySize){
            return generateVerifyCode(verifySize, VERIFY_CODES);
        }
        /**
         * 使用指定源生成验证码
         * @param verifySize    验证码长度
         * @param sources   验证码字符源
         * @return
         */
        public static String generateVerifyCode(int verifySize, String sources){
            if(sources == null || sources.length() == 0){
                sources = VERIFY_CODES;
            }
            int codesLen = sources.length();
            Random rand = new Random(System.currentTimeMillis());
            StringBuilder verifyCode = new StringBuilder(verifySize);
            for(int i = 0; i < verifySize; i++){
                verifyCode.append(sources.charAt(rand.nextInt(codesLen-1)));
            }
            return verifyCode.toString();
        }

        /**
         * 生成随机验证码文件,并返回验证码值
         * @param w
         * @param h
         * @param outputFile
         * @param verifySize
         * @return
         * @throws IOException
         */
        public static String outputVerifyImage(int w, int h, File outputFile, int verifySize) throws IOException{
            String verifyCode = generateVerifyCode(verifySize);
            outputImage(w, h, outputFile, verifyCode);
            return verifyCode;
        }

        /**
         * 输出随机验证码图片流,并返回验证码值
         * @param w
         * @param h
         * @param os
         * @param verifySize
         * @return
         * @throws IOException
         */
        public static String outputVerifyImage(int w, int h, OutputStream os, int verifySize) throws IOException{
            String verifyCode = generateVerifyCode(verifySize);
            outputImage(w, h, os, verifyCode);
            return verifyCode;
        }

        /**
         * 生成指定验证码图像文件
         * @param w
         * @param h
         * @param outputFile
         * @param code
         * @throws IOException
         */
        public static void outputImage(int w, int h, File outputFile, String code) throws IOException{
            if(outputFile == null){
                return;
            }
            File dir = outputFile.getParentFile();
            if(!dir.exists()){
                dir.mkdirs();
            }
            try{
                outputFile.createNewFile();
                FileOutputStream fos = new FileOutputStream(outputFile);
                outputImage(w, h, fos, code);
                fos.close();
            } catch(IOException e){
                throw e;
            }
        }

        /**
         * 输出指定验证码图片流
         * @param w
         * @param h
         * @param os
         * @param code
         * @throws IOException
         */
        public static void outputImage(int w, int h, OutputStream os, String code) throws IOException{
            int verifySize = code.length();
            BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
            Random rand = new Random();
            Graphics2D g2 = image.createGraphics();
            g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);
            Color[] colors = new Color[5];
            Color[] colorSpaces = new Color[] { Color.WHITE, Color.CYAN,
                    Color.GRAY, Color.LIGHT_GRAY, Color.MAGENTA, Color.ORANGE,
                    Color.PINK, Color.YELLOW };
            float[] fractions = new float[colors.length];
            for(int i = 0; i < colors.length; i++){
                colors[i] = colorSpaces[rand.nextInt(colorSpaces.length)];
                fractions[i] = rand.nextFloat();
            }
            Arrays.sort(fractions);

            g2.setColor(Color.GRAY);// 设置边框色
            g2.fillRect(0, 0, w, h);

            Color c = getRandColor(200, 250);
            g2.setColor(c);// 设置背景色
            g2.fillRect(0, 2, w, h-4);

            //绘制干扰线
            Random random = new Random();
            g2.setColor(getRandColor(160, 200));// 设置线条的颜色
            for (int i = 0; i < 20; i++) {
                int x = random.nextInt(w - 1);
                int y = random.nextInt(h - 1);
                int xl = random.nextInt(6) + 1;
                int yl = random.nextInt(12) + 1;
                g2.drawLine(x, y, x + xl + 40, y + yl + 20);
            }

            // 添加噪点
            float yawpRate = 0.05f;// 噪声率
            int area = (int) (yawpRate * w * h);
            for (int i = 0; i < area; i++) {
                int x = random.nextInt(w);
                int y = random.nextInt(h);
                int rgb = getRandomIntColor();
                image.setRGB(x, y, rgb);
            }

            shear(g2, w, h, c);// 使图片扭曲

            g2.setColor(getRandColor(100, 160));
            int fontSize = h-4;
            Font font = new Font("Algerian", Font.ITALIC, fontSize);
            g2.setFont(font);
            char[] chars = code.toCharArray();
            for(int i = 0; i < verifySize; i++){
                AffineTransform affine = new AffineTransform();
                affine.setToRotation(Math.PI / 4 * rand.nextDouble() * (rand.nextBoolean() ? 1 : -1), (w / verifySize) * i + fontSize/2, h/2);
                g2.setTransform(affine);
                g2.drawChars(chars, i, 1, ((w-10) / verifySize) * i + 5, h/2 + fontSize/2 - 10);
            }

            g2.dispose();
            ImageIO.write(image, "jpg", os);
        }

        private static Color getRandColor(int fc, int bc) {
            if (fc > 255)
                fc = 255;
            if (bc > 255)
                bc = 255;
            int r = fc + random.nextInt(bc - fc);
            int g = fc + random.nextInt(bc - fc);
            int b = fc + random.nextInt(bc - fc);
            return new Color(r, g, b);
        }

        private static int getRandomIntColor() {
            int[] rgb = getRandomRgb();
            int color = 0;
            for (int c : rgb) {
                color = color << 8;
                color = color | c;
            }
            return color;
        }

        private static int[] getRandomRgb() {
            int[] rgb = new int[3];
            for (int i = 0; i < 3; i++) {
                rgb[i] = random.nextInt(255);
            }
            return rgb;
        }

        private static void shear(Graphics g, int w1, int h1, Color color) {
            shearX(g, w1, h1, color);
            shearY(g, w1, h1, color);
        }

        private static void shearX(Graphics g, int w1, int h1, Color color) {

            int period = random.nextInt(2);

            boolean borderGap = true;
            int frames = 1;
            int phase = random.nextInt(2);

            for (int i = 0; i < h1; i++) {
                double d = (double) (period >> 1)
                        * Math.sin((double) i / (double) period
                        + (6.2831853071795862D * (double) phase)
                        / (double) frames);
                g.copyArea(0, i, w1, 1, (int) d, 0);
                if (borderGap) {
                    g.setColor(color);
                    g.drawLine((int) d, i, 0, i);
                    g.drawLine((int) d + w1, i, w1, i);
                }
            }

        }

        private static void shearY(Graphics g, int w1, int h1, Color color) {

            int period = random.nextInt(40) + 10; // 50;

            boolean borderGap = true;
            int frames = 20;
            int phase = 7;
            for (int i = 0; i < w1; i++) {
                double d = (double) (period >> 1)
                        * Math.sin((double) i / (double) period
                        + (6.2831853071795862D * (double) phase)
                        / (double) frames);
                g.copyArea(i, 0, 1, h1, 0, (int) d);
                if (borderGap) {
                    g.setColor(color);
                    g.drawLine(i, (int) d, i, 0);
                    g.drawLine(i, (int) d + h1, i, h1);
                }

            }

        }
}
